EXPANDALBE ANODE ASSEMBLY

Abstract

An array of anode assemblies for insertion at a plurality of locations in a gap between a section of a reinforced concrete structure and another solid structure is provided. Each anode assembly comprises an expandable member, an anode attached to the expandable member for protecting a steel reinforcement in the reinforced concrete structure, and an anode connector for interconnecting the array of anode assemblies. During use, each anode assembly of the array of anode assemblies is inserted into the gap, between the section of the reinforced concrete structure and the solid structure, at the plurality of locations. The expandable member of each anode assembly is configured to expand so as to press the anode into contact with a surface of the reinforced concrete structure.

Claims

1. An array of anode assemblies for insertion at a plurality of locations in a gap between a section of a reinforced concrete structure and another solid structure, wherein each anode assembly comprises an expandable member, an anode attached to the expandable member for protecting a steel reinforcement in the reinforced concrete structure, and an anode connector for interconnecting the array of anode assemblies, whereby in use, each anode assembly of the array of anode assemblies is inserted into the gap, between the section of the reinforced concrete structure and the solid structure, at the plurality of locations, and the expandable member of each anode assembly is configured to expand so as to press the anode into contact with a surface of the reinforced concrete structure.

2. The array of anode assemblies according to claim 1, wherein the expandable member of each anode assembly comprises a compressed compressible material, and the compressible material of each anode assembly assembly is configured to expand so as to press the anode into contact with a surface of the reinforced concrete structure.

3. The array of anode assemblies according to claim 2, wherein each anode assembly comprises a flexible enclosure, and the compressible material is sealed within the flexible enclosure under air-evacuated conditions, and and the anode is attached to an exterior of the flexible enclosure, whereby in use, the compressible material expands to press the anode into contact with a surface of the reinforced concrete structure when air is caused to re-enter the flexible enclosure.

4. The array of anode assemblies according to claim 3, wherein the flexible enclosure is made of a plastic material.

5. The array of anode assemblies according to claim 3, wherein the flexible enclosure is made of a thermoplastic material.

6. The array of anode assemblies according to claim 3, wherein the flexible enclosure comprises an air-impermeable layer.

7. The array of anode assemblies according to claim 3, wherein the flexible enclosure comprises a heat-sealable material.

8. The array of anode assemblies according to claim 3, wherein an inner surface of the flexible enclosure is dimpled.

9. The array of anode assemblies according to claim 2, wherein the compressible material is an open cell foamed material.

10. The array of anode assemblies according to claim 9, wherein the open cell foamed material has a density greater than 30 kg/m3.

11. The array of anode assemblies according to claim 9, wherein the open cell foamed material comprises a polyurethane.

12. The array of anode assemblies according to claim 3, wherein the flexible enclosure comprises a heat seal for sealing the compressible material inside the flexible enclosure.

13. The array of anode assemblies according to claim 1, wherein each anode is a discrete anode and the anode connector of each anode assembly is interconnected via an interconnecting conductor.

14. The array of anode assemblies according to claim 1, wherein each anode is an inert anode for use in an impressed current cathodic protection treatment or a sacrificial anode for use in a sacrificial cathodic protection treatment.

15. The array of anode assemblies according to claim 1, wherein at least one anode assembly comprises a second anode attached to the expandable member opposite the attached anode.

16. The array of anode assemblies according to claim 3, wherein at least one anode assembly comprises a second anode attached to the expandable member opposite the attached anode, and the second anode is provided on an exterior surface of the flexible enclosure opposite the attached anode.

17. The array of anode assemblies according to claim 1, wherein the anode is attached to the expandable member using an elastomeric adhesive.

18. The array of anode assemblies according to claim 1, wherein a ratio of unexpanded to expanded assembly thickness is at least 1:2.

19. The array of anode assemblies according to claim 1, wherein the ratio of unexpanded to expanded assembly thickness is from about 1:2 to about 1:10.

20. The array of anode assemblies according to claim 1, wherein each anode measures at most 400 mm (15.748 inches) by 400 mm (15.748 inches).

21. The array of anode assemblies according to claim 1, wherein each anode assembly has a maximum thickness, in an unexpanded state, of at most 15 mm (0.591 inches).

22. The array of anode assemblies according to claim 1, wherein each anode comprises a first and a second layer of anode material, the anode connector extending between the first and second layers of anode material, thereby forming a connection with the anode, and the first and second layers of anode material comprise zinc.

23. The array of anode assemblies according to claim 22, wherein the first and second layers of anode material are welded together, thereby securing the anode connector therebetween.

24. The array of anode assemblies according to claim 1, wherein the anode connector comprises titanium.

25. The array of anode assemblies according to claim 3, wherein at least one anode assembly comprises a first flexible enclosure and a second flexible enclosure arranged next to the first flexible enclosure, and a compressible material sealed within each flexible enclosure, under air-evacuated conditions in each flexible enclosure, whereby in use, the at least one anode assembly is inserted into the gap between the section of the reinforced concrete structure and the solid structure with the compressible material in the first and/or second flexible enclosure in a compressed state, the compressible material in the first and/or second flexible enclosure being configured to expand so as to press the anode into contact with a surface of the reinforced concrete structure when air is caused to re-enter the first and/or second flexible enclosure.

26. The array of anode assemblies according to claim 25, wherein the first flexible enclosure is attached to the second flexible enclosure.

27. The array of anode assemblies according to claim 26, wherein the first flexible enclosure is attached to the second flexible enclosure by an adhesive.

28. The array of anode assemblies according to claim 15, comprising a first and a second anode, wherein the first and second anodes are attached on corresponding exterior surfaces of the first and second flexible enclosures, facing away from one another.

29. The array of anode assemblies according to claim 1, comprising at least three anode assemblies.

30. The array of anode assemblies according to claim 30, wherein at least one of the anode assemblies comprises a reference electrode mounted to and electrically isolated from the anode, and a reference electrode conductor for connecting the reference electrode to measuring apparatus, the reference electrode conductor being electrically isolated from the anode.

31. The array of anode assemblies according to claim 1, wherein the anode assemblies are arranged at a density of at least two assemblies per square meter of reinforced concrete surface.

32. A structure comprising a gap between a section of a reinforced concrete structure and another solid structure, the structure containing in the gap the array of anode assemblies according to claim 1.

33. An anode assembly for insertion in a gap between a section of a reinforced concrete structure and another solid structure, wherein the anode assembly comprises a flexible enclosure; a compressible material sealed within the flexible, enclosure under air-evacuated conditions, and an anode attached to an exterior surface of the flexible enclosure for protecting a steel reinforcement in the reinforced concrete structure, whereby in use, the compressible material expands to press the anode into contact with a surface of the reinforced concrete structure when air is caused to re-enter the flexible enclosure.

34. A method of producing an anode assembly adapted for insertion into a gap between a section of a reinforced concrete structure and another solid structure, the method comprising the steps of: providing an expandable member in an unexpanded state; and attaching an anode to the expandable member; wherein the unexpanded expandable member is suitable for expanding so as to press the anode into contact with a surface of the reinforced concrete structure.

35-45. (canceled)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0049] In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0050] FIG. 1 shows a perspective view of an expanding component of a single anode assembly.

[0051] FIG. 2 shows a perspective view of the expandable anode assembly.

[0052] FIG. 3 shows a perspective view of an array of expandable anode assemblies installed in a gap between two concrete elements.

[0053] FIG. 4 shows an exploded view of a single anode assembly according to a second embodiment.

[0054] FIG. 5 shows an exploded view of a single anode assembly according to a third embodiment.

[0055] FIG. 6 shows an exploded view of a single anode assembly according to a fourth embodiment.

EXAMPLE 1

[0056] The expanding component of the anode assembly was constructed using blocks of foam 1, a vacuum packing machine (not shown) and vacuum pouches 2. The foam block 1 was polyurethane upholstery foam with a density of about 50 kg/m.sup.3. The foam 1 was resilient as opposed to a memory foam and measured about 18510547 mm.

[0057] The pouch 2 measured 300200 mm when stored flat and was made of a clear (see through) plastic. In particular, the pouch 2 is made from a polyamide air impenetrable exterior and a polyethylene interior. The vacuum pouches 2 and vacuum packing machine were obtained from lava vacuum packing, and were manufactured in Germany by Manfred Landig. The vacuum packing machine used was the LAVA V.100 Classic vacuum Sealer.

[0058] Each foam block 1 was placed inside the vacuum pouch 2 which in turn was placed on a flat surface next to the vacuum packing machine. An A4 sized book weighing about 1 kg was placed on top of the pouch 2 and foam 1 to keep the pouch 2 flat as air was evacuated.

[0059] The opening 3 to the pouch was inserted into the vacuum packing machine. Air was evacuated until a vacuum of about 0.8 bar was generated in the pouch 2 to form an evacuated pouch 5. This places the foam block under a pressure of about 11.6 lb/in.sup.2 (about 8150 kg/m.sup.2).

[0060] The pouch opening 3 was then sealed securely to prevent air from getting back in by making a heat seal 7. A heated surface in the machine presses the pouch closed and slightly melts the plastic of the pouch to make the heat seal 7. The sealed pouch contained a compressed foam block 6, with a thickness that reduced from 47 mm to about 6 mm in a substantially flat 300200 mm pouch 5.

[0061] The position of the compressed foam 6 in the evacuated pouch 5 was visible because the evacuated pouch 5 was clear. The compressed foam 6 substantially retained the other dimensions of the foam block 1 measuring 185105 mm. The compressed foam 6 was left compressed in the evacuated pouch 5 for a period of time before letting air back into the pouch, e.g. by deliberately puncturing the evacuated pouch 5. The recovery of the foam 1 was then observed to assess whether it had suffered any plastic deformation while compressed. The results are shown in Table 1 as a percentage recovery of the foam thickness. The data shows that a compressed anode assembly 22 may be stored without any substantial loss of resilience. Moreover, elapsed time while compressed appears to have no noticeable impact up to 6 days. All expanded samples are about the same thickness but there was a non-significant amount of plastic deformation in the foam.

TABLE-US-00001 TABLE 1 Elapsed Time % Recovery 10 minutes 100% 6 hours 90% 2 days 90% 6 days 90%

EXAMPLE 2

[0062] A single anode assembly 22 according to the present invention is best shown in FIG. 2. The assembly comprises a compressed foam 10, an evacuated vacuum pouch 11, a sheet of zinc 12 attached to an outer surface of the evacuated vacuum pouch 11, an adhesive (not shown), optionally a second sheet of zinc 13 and an electrical connector 14.

[0063] The compressed foam block 10 inside the sealed evacuated vacuum pouch 11 was prepared as described in Example 1. The foam block measured 18510547 mm before compression. The zinc plate 12, 13 was obtained from a zinc sheet supplier and was cut to a size of 105185 mm. It was about 0.5 mm thick and weighed 130 grams.

[0064] The zinc plate, 12, 13 was prepared for use as an anode by soldering a copper core electric cable to the back of the plate 12, 13 and connecting it to a plastic coated titanium wire. The connection 14 was insulated with the exception of a short length of titanium that protruded just beyond the anode surface. This formed the point to connect the zinc plate 12, 13 anode to the rest of the system. Other exposed portions of conductor were covered with a Dow Corning high movement silicone.

[0065] The Dow Corning high movement silicone was used as an adhesive to attach the zinc plate 12, 13 to the pouch 11. Spots of silicone where applied to the surface of the zinc plate 12, 13 that included the connection 14. It was then positioned to contact the pouch 11 such that it covered the compressed foam block 10 in the pouch 11. The adhesive was then left to set. The overall thickness of the assembly 22 before it set was just 10 mm.

EXAMPLE 3

[0066] FIG. 3 shows an array of anode assemblies 22 installed in a gap 21 between reinforced concrete elements 20. To install the anode assemblies 22, the gap 21 at the joint between the concrete elements is cleared of debris to prepare it to receive the anode assemblies 22. The assemblies 22 are then prepared for insertion into the gap 21. This may include removing any external packaging and/or applying a thin layer of bedding material over the surface of the anode 12, 13 of the assembly 22 to facilitate electrolytic contact with the surface of the reinforced concrete elements 20. In this embodiment the bedding material was lime putty.

[0067] The anode assemblies 22 are then inserted into the gap 21 and arranged so that the assembly connectors 24 are exposed at the edge of the gap 21. The evacuated pouches 11 of the anode assembly 22 are then punctured (the seal is broken) to allow the assembly to expand and press the anode(s) 12, 13 of the assembly 22 against the surface(s) of the reinforced concrete elements 20 in the gap 21 and effectively hold the anode 12, 13 in place. An interconnecting conductor 23 is then used to connect the anode connectors 14 together at anode connections 24.

[0068] To complete the circuit a connection will also be made to the steel reinforcement. If sacrificial protection current is to be delivered the anodes will be sacrificial anodes (e.g. zinc) and will be connected directly to the steel. If impressed current is to be delivered the anodes may be inert anodes (e.g. activated titanium) and the anodes will be connected to the positive terminal of a DC power supply, while the steel will be connected to the negative terminal of that power supply.

EXAMPLE 4

[0069] FIG. 4 shows an exploded view of another embodiment of an anode assembly for installation as part of an anode assembly array.

[0070] The anode assembly comprises a first zinc plate 12. As shown, the zinc plate comprises a first layer of zinc 12a and a second layer of zinc 12b. The second layer of zinc 12b is significantly smaller than the first layer of zinc 12a and defines an attachment region of the anode, in which the connector 14 is connected to the anode. Specifically, the connector 14, which is a titanium connector in this embodiment, extends between the first layer of zinc 12a and the second layer of zinc 12b in the attachment region. The second layer of zinc 12b is spot welded to the first layer of zinc at eight different locations 15 across the attachment region, although the number of spot weld points 15 can be varied as needed. This arrangement sandwiches the connector between the layers of zinc in the attachment region, firmly securing the connector to the anode and providing an electrical connection therewith.

[0071] This embodiment also contains first and second evacuated vacuum pouches 11, 11, each comprising a respective compressed foam 10, 10 as described above. The first zinc plate 12, which acts as the anode, is attached to the first evacuated vacuum pouch in the manner described above on a first surface of the first pouch 11. The second pouch 11 is arranged on a second surface of the first pouch 11, opposite the first surface. The second pouch 11 is joined to the first pouch 11 by an adhesive (not shown).

[0072] When the anode assembly is installed in a gap, typically as part of an array, both the first and second pouches 11, 11 are punctured, for example, such that the first and second pouches expand together and press the anode against a concrete surface to be protected. The use of at least two pouches 11, 11 in this manner allows for larger gaps to be accommodated by the anode assembly.

EXAMPLE 5

[0073] FIG. 5 shows an exploded view of another embodiment of an anode assembly for installation as part of an anode assembly array.

[0074] This embodiment is identical to the previous embodiment, but further comprises a second anode zinc plate 12 with a corresponding second connector 14. Specifically, the second zinc plate 12 is arranged on the outer facing surface of the second pouch 11. The second zinc plate is attached to the second pouch in the manner described above, i.e. using Dow Corning high movement silicone as an adhesive. In this embodiment, as the first and second pouches expand together and press the first anode against a first concrete surface to be protected, they simultaneously press the second anode 12 against a second concrete surface to be protected, i.e. a concrete surface facing the first concrete surface.

[0075] In practice, this embodiment may be formed on site by adhering together two identical anode assemblies such as described above with reference to FIG. 2. This allows one design of anode assembly to be adaptable to an increased range of on-site requirements.

EXAMPLE 6

[0076] FIG. 6 shows an exploded view of another embodiment of an anode assembly for installation as part of an anode assembly array.

[0077] This embodiment again comprises a single evacuated pouch 11 comprising a compressed foam 10, as described above with reference to FIG. 2. The assembly also comprises a zinc plate made up of a first layer of zinc 2a and a second layer of zinc 12b, as described above with respect to FIG. 4.

[0078] In addition, the anode assembly of this embodiment comprises a reference electrode 16. The reference electrode is mounted on a surface of the first layer of zinc 12a of the zinc plate facing the evacuated pouch 11, outside of the attachment region defined by the second layer of zinc 12b. The reference electrode comprises an insulating ring 17 that isolates a reference electrode core 18, located within the insulating ring, from the first layer of zinc 12a of the zinc plate 12. The insulating ring 17 may be made from any insulating material, for example rubber. The electrode core 18, in this embodiment, comprises an activated titanium mesh embedded in a lime cement. An insulated connecting wire 19 extends from the electrode core 18 between the first layer of zinc 12a of the zinc plate and the pouch 11 out and away from the assembly for connecting the reference electrode to measuring equipment (not shown).

[0079] The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.